yes i have done Gorilla trekking in several occasions not only once and i have a wide experience on it. Iam very sure you donot need a hiking shoes unless you have other activities of hiking after Gorilla trekking, Camera is recommended though they do not allow flashing cameras when your with Gorillas, the camera should not necessarily be zoom lense since you will be close to these apps when your trekking.
For camping equipments it depends on the type of the accommodation you have booked with your traveling agency who organizes for your trip but trekking Gorillas takes between 30 mins to 8 hours depending on where the Gorillas had spent their last night, but after trekking you will come back to your lodge for dinner and over night. Lunches you will go with parked lunch .
thanks very much i hope my information will help you .